| 摘要 |
PROBLEM TO BE SOLVED: To keep a discharge lamp like a high pressure sodium lamp in a illuminating state, in the case of instantaneous failure of the commercial power supply, without leaving it in an unlighted state. SOLUTION: The discharge lamp lighting device comprises a discharge lamp LA, a rectifier 10, a step-up chopper 11, a step-up control circuit 12, a filter capacitor C10, a step-down chopper 13, a step-down control circuit 14, a filter 15, an inverter 16, and an igniter 17. The filter capacitor C10 has enough capacitance to keep the discharge lamp lighted during instantaneous failure of the alternating power source Vs, and a capacitor C18 has capacitance to make the step-down control circuit 14 operate at start. A start power source 18 and a control power source 19 are installed in order to make the step-down control circuit 14 start operation prior to the operation of the step-up control circuit 12. |
